Research On The Key Technology Of Stealth Micro Satellite Structure Design

Under the needs of national military and sapce resources exploration, the satellite is developingforword to miniaturization, functionalization and modularization rapidly. By continuously renew ofthe micro electromechanical, new material and other hi-tech, the development of small satellite andmicro satellite is springing up over the world. As the important technical foundation for satellitesystem, structure design is not only directly related to the success of the satellite launch, but also is thebasic guarantee for the satellite comprehensive properties implementation. Taking the stealth microsatellite as the background, which is designed by Nanjing university of aeronautics andastronautics, the researchs were carried out form the ascepts of stealth configuration design, primaryload bearing structure design, structure multi-objective optimization design and dynamicenvironmental test design. The concrete contents are as following:1. By meeting the needs of dimension constraints and the stealth performance, according to thepolygon design thought, a diamond-type configuration design scheme is proposed. Its bottom ishexagonal-prism, the middle is hexagonal-prismoid and the top is hexagonal-pyramid. By analyzingthe scattering characteristics of the mirco satellite, the radar scattered section is predicted using highfrequency methods. A real-size metal satellite model is made for the RCS measurement at C bands ina microwave darkroom. By comparison and analysis, the rationality of the scheme is determined.2. A method for primary load bearing structure of the micro satellite is proposed. The method notonly meets the need of structure stiffness and rationality for the force transfer path, but alsoimplements the layout of the satellite equipments. Taking the stealth mirco satellite for example, theprimary load bearing structure is designed comprehensive, based on the stealth configuration. Thesatellite adapter, the floor, the diaphragm and other force bearing parts are also designed respectively.3. The multi-objective optimization design is carried out for the primary load bearing structure ofthe micro satellite.Both the satellite stiffness and the primary load bearing structure mass is taken asthe objective function. The design variable contains the thickness of aluminum panels, core plates andskeleton. An improved trust-region approximation model management frame is proposed subject tothe low precision of the ordinary approximation model for comprehensive engineering problems. Theadvantages of this method are that the optimization results are little influenced by approximationmodel during the solving process. By using max-min distance means, several maximum distancesolutions evaluated by real model are selected from the last pareto optimization solutions. Then, searching area is renewed according to the evaluation result, thus the final solutions are uniform to thereal pareto solutions. The method is demonstrated by four different classical test functions andsuccessfully applied in the micro satellite structure optimization design. By comparing with the valuesof the objective function after optimization, good effect is obtained.4. After modified the micro satellite structure parameters, the optimized FEM is built. By usingthe PATRAN/NASTRAN software for static analysis, the satellite strength is evaluated. Meanwhile,according to the general and equipments design requirements of the satellite, frequency responseanalysis and random vibration analysis are calculated in the software. From the analysis andcalculation, the dynamic response characteristics of the structure parts and equipments are obtained.Meanwhile, the results provide reference for dynamic environmental test design.5. Considering the high reliability for satellite structure design, the mechanical environmentaltest design scheme is proposed, based on the simulated results. It takes the aim at verifying therationality of the structure design and optimization method, requiring the structure static and dynamiccharacteristics. By acquiring and analyzing the sine-vibration and random vibration test datas underacceptance and identification grade, the effectiveness and rationality of the approximation modelmanagement method and the FEM building is verified. The mechanical environmental test providereliable basis for formal satellite local adjustment and other micro satellites structure and test designin future.